Technical Field
The present invention generally relates to metallization for semiconductor devices. More particularly, the present invention relates to improving copper seed coverage during Back End of the Line (BEOL) metallization.
Background Information
As devices shrink, metallization becomes more of a problem and sufficient copper seed coverage over the device feature becomes critical. Discontinuous copper seed coverage leads to poor copper plating and a “copper line void.” One attempted solution uses a sacrificial silicon nitride layer, which is removed using dilute hydrofluoric acid prior to formation of copper barrier and copper seed layers. The effect lowers the overall dielectric height to improve the copper seed coverage over the features. However, while metallization defects improved, the sacrificial silicon nitride itself may introduce other defects and potentially lend to dielectric breakdown.
Thus, a need exists for a way to reduce or eliminate discontinuous copper seed coverage in BEOL metallization.